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Thanks everyone for all the suggestions. Since I have tried everything I can think of and nothing makes any difference I can only think that my piston to cylinder liner fit is no good. I don't know what good compression should feel like. For comparison as I mentioned I have an OS Max 40 and it...

Hi, As suggested by f2cf1g I drained the crankcase, I splashed fuel as suggested, It ran on prime, I reconnected fuel hose opened 1.5 turns continued to fire a few times as before. So I did the skimming to increase the compression ratio. Still the same result no matter what I do. Glow plug is...

Thank you Mechanicboy and f2cf1g. I read the documents that were pointed out to me , thanks for that. I will try all the suggestions mentioned. I am using a hot glow plug. I may be experiencing the hydraulic lock mentioned as sometimes after it fires the prop stops/locks on the down stroke. This...

I have tried infinite fuel needle positions. The needle was 1/4 turn from closed in this case. It does not seem to make any difference. I can even disconnect the fuel line, close the needle, prime with direct inject into venturi and it will run like that off the prime alone. I made a new needle...

The plans I went from say the compression ratio is 8.3 :1. I have teflon seal at cylinder base and aluminium foil at head. I cannot see leaks. After weeks of trying the best I get is a 2 second run. See if the video sound gives anyone a clue what might be wrong.

Hi Mechanicboy, The piston to cylinder liner fit is as you described. I have done the lapping job as described. What I was saying was that the cylinder liner fitting into the aluminium cylinder/crankcase is not a very tight fit. I think if it leaks between the steel liner and the aluminium that...

HI, Thanks for your responses. I do understand the principals you explain and I have built the engine according to plans on this site so if the compression ratio is whatever the design produced. I do understand what you mean by 'poof' sound from transfer port opening and I believe I get this...

Well, I have checked the piston, remade the front housing for crankshaft , remade venturi, remade cylinder liner to lower the transfer ports, sealed front housing and backplate with gasket sealant, made gasket for cylinder to crankcase yet I still cannot get it to keep running. It will fire...

Thanks for the info. I will check the piston size again but I did follow the drawings. I certainly feel a pull on the downstroke. When you say bypass, whats that? Is it the vertical channels in the cylinder wall that transfer fuel from the crankcask to the combustion chamber?. I will remake the...

Hello Ved, I found some info on a web site somewhere but cant remember which one. It works with Cast Iron so all you do is heat the piston till its glowing red hot, mine was almost orange then quench it in oil. I just used motor oil. Do it outside and drop completely in the oil otherwise you can...

Thanks for all the info GaillnNM and Cogsy. I have almost given up hope. I can confirm spray bar facing correct direction and blowing down fuel hose with needle closed shows it is truely seated. Ports are facing correct direction and transfer ports close before exhaust port. Will check...

Hi Cogsy, I followed the plans and the needle taper is as drawn, and yes I am hand flipping the engine. So if I start from a dry engine, should I prime it at all. When I was in my 20's I flew RC planes. Priming was open throttle, needle 1.5 turns out, block carb air intake, flip prop several...

Hello minh, Absolutly, there is resistance and popping sound. The engine also fires when igniter is connected.

Still struggleing to get this to run. I remade the cylinder liner as I missread the plan and cut the transfer ports too high. The new liner has the transfer ports at the correct height. I have good glow on the plug, i see fuel is getting to the combustion chamber, I get it to fire on almost...

I followed the plans for needle taper as best I could. How many turns out should I start with?

Hi, I discovered this forum while searching for projects to build with my lathe. I purchase a lathe around 4 months ago. I have never used a lathe before but wanted to make an IC engine. First I just made some simple bushes, Kurled knobs, ornaments and a Gyroscope.. I found the MP3.2 plans on...